Rotary percussion drill having a hydraulically actuated percussion device

ABSTRACT

The percussive forces are imparted to the drill rod by a hydraulically actuated reciprocating piston housed in a cylinder having fluid openings on opposite sides of the piston. Fluid under pressure is supplied alternately to the respective openings to reciprocate the piston in the cylinder from a multi-valve control device. A timing mechanism is included in the multi-valve control device to open and close the valve ports within the valve to supply pressurized fluid alternately to the openings in the cylinder on opposite sides of the piston and to alternately vent the pressurized fluid from the cylinder. Pressure accumulators are employed as surge devices for excess fluid supplied to the cylinder for each stroke of the piston.

United States Patent [151 3,654,961 [451 Apr. 11,1972

Phillips [54] ROTARY PERCUSSION DRILL HAVING A HYDRAULICALLY ACTUATEDPERCUSSION DEVICE [72] Inventor: Albert Phillips, 465 Kiwanis Avenue,Morgantown, W. Va. 26505 [22] Filed: July 31, 1970 [21] Appl. No.:60,023

Related U.S. Application Data [62] Division of Ser. No. 807,388, Mar.14, 1969, Pat. No.

[52] U.S. Cl ..137/624.l3, l37/624.l8, l37/596.l8, 9l/36 [5 1] Int. Cl..F15b 21/02 [58] Field of Search ..l37/624.l8, 624.2, 624.19,137/624.l5, 596, 596.18; 91/39, 36

[56] References Cited UNITED STATES PATENTS 3,022,738 2/1962 Krute..9l/39 3,399,698 9/1968 Bentley ..l37/624.2X 3,273,593 9/1966 Kinsley..l37/624.2X

Primary Examiner-Alan Cohan Attorney-Stanley J. Price, Jr.

[57] ABSTRACT The percussive forces are imparted to the drill rod by ahydraulically actuated reciprocating piston housed in a cylinder havingfluid openings on opposite sides of the piston. Fluid under pressure issupplied alternately to the respective openings to reciprocate thepiston in the cylinder from a multi-valve control device. A timingmechanism is included in the multi-valve control device to openand closethe valve ports within the valve to supply pressurized fluid alternatelyto the openings in the cylinder on opposite sides of the piston and toalternately vent the pressurized fluid from the cylinder. Pressureaccumulators are employed as surge devices for excess fluid supplied tothe cylinder for each stroke of the piston.

9 Claims, 13 Drawing Figures PATENTEDAPR 1 1 I972 SUCTION PUMP SUCTION q5/2 PUMP 1 span F -11- nsoucsn 5/8 sucr/o/v n u INVENTOI? .4 BERTPHILLIPS PNENTEDAPR 1 1 I972 SHEET 5 BF 5 INVENTOR AL BERT PH/Ll. IPS

Br ti 7:; 4

his A Her/ray ROTARY PERCUSSION DRILL HAVING A HYDRAULICALLY ACTUATEDPERCUSSION DEVICE CROSS REFERENCE TO RELATED APPLICATIONS Thisapplication is a division of U. S. application Ser. No. 807,388, filedMar. 14, 1969 and entitled Rotary Percussion Drill Having aHydraulically Actuated Percussion Device" now US. Pat. No. 3,547,206issued Dec. 15, 1970.

BACKGROUND OF THE INVENTION 1 Field of the Invention This inventionrelates to a hydraulically actuated reciprocating device and moreparticularly to a hydraulically actuated reciprocating piston percussiondevice with control means to supply fluid under pressure alternately toopposite faces of a piston.

2. Description of the Prior Art In underground mines, the roof of theentries or tunnels are supported by expansion type roof bolts. The boltsare inserted in drilled holes that are, arranged in predetermined spacedpatterns. The drilling of the bolt holes consumes a substantial amountof time and contributes substantially to the overall cost of the miningoperation. The bolt holes were, in the past, drilled by rotary drillsand it was found by using a high rotary speed and imparting percussiveforces to the drill rod, that it was possible to increase the rate ofpenetration of the drill rod and thus reduce the time required to drillthe bolt holes. The percussive forces applied to the drill rod wereimparted either by the conventional air type reciprocating devices wellknown in the percussive drill art or imparted by the action of eccentricweights. The use of air underground, especially in coal mines, isdiscouraged because the exhaust air adjacent the drill rod increases thedust hazards. There have been several proposals in the past of impartingthe percussive forces to the drill rod by a hydraulically actuateddevice. To the best of my knowledge none of these devices have beencommercially successful. There is a need, therefore, for a hydraulicallyactuated percussive device that may be used with a percussion drill orassociated with a high speed rotary drill to impart percussive forcesthereto.

SUMMARY OF THE INVENTION The herein described invention relates to ahydraulically actuated reciprocating piston. Hydraulic fluid underpressure is supplied alternately to the piston cylinder assembly onopposite sides of the piston from a multi-valve control device to openand close the valve ports within the valve to supply pressurized fluidalternately to opposite sides of the piston and to alternately vent thecylinder on opposite sides of the piston so that the timing devicecontrolling the opening and closing of the valves thereby control therate of reciprocation of the piston. The timing device may also beemployed as a positive displacement pump to supply the fluid to thecontrol valves. The piston cylinder assembly may be connected to eithera percussive drill or to a high speed rotary drill to impart percussiveforces to the rotating drill rod.

The principal object of this invention is to provide a fluid actuateddevice that includes a multi-valve control device which alternatelysupplies fluid under pressure to opposite sides of a reciprocatingpiston within a cylinder.

Another object of this invention is to provide a reciprocating devicewherein the timing device for supplying pressurized fluid to oppositesides of a reciprocating piston within a cylinder also functions as apositive displacement pump.

Another object of this invention is to provide a reciprocating device inwhich the cylinders on opposite sides of the piston are connected topressure ports and vent ports of a multi-valve control device andaccumulator devices are provided to displace the excess fluid suppliedto the cylinder.

Another object of this invention is to provide a reciprocating piston inwhich the cylinder is provided with a liquid shock absorbing means forthe piston at opposite ends of its stroke.

Another object of this invention is to provide a percussion drill with ahydraulically actuated percussion device.

Another object of this invention is to provide a reciprocating devicewherein the volume of liquid displaced by a timing and metering devicewill correspond with the volume of liquid required to displace thepiston in the cylinder for a complete stroke of the piston.

These and other objects and advantages of this invention will be morecompletely disclosed and described in the following specification, theaccompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a view in elevation of the multi-valve control deviceillustrating the plurality of inlet and outlet ports for the pressureand vent valves and the timing device.

FIG. 2 is a view in section taken along the line IIII of FIG. 1illustrating in detail the plurality of valves in their operativepositions and the gears of the timing device.

FIG. 3 is a view in section of a rotary percussion drill head with acylinder housing the reciprocating piston and having pairs of openingson opposite sides of the piston.

FIG. 4 is a view in section of the pressure accumulators illustrated inFIG. 1 connected to the vent or return conduit.

FIG. 5 is a view in section taken along the line V-V of FIG. 2illustrating one of the pressure valves in open position.

FIG. 6 is a view in section taken along the line VI-VI illustrating oneof the vent valves in a closed position.

FIG. 7 is a view in section taken along the line VII-VII in FIG. 2illustrating in detail the timing gears that may also function as apositive displacement pump.

FIG. 8 is a view taken along the line VIII-VIII of FIG. 5 illustratingone of the rotary disc-like valve members with a peripheral flow recesspassage through a portion thereof.

FIG. 9 is a schematic view illustrating the motor driven valve where thetiming device also functions as a positive displacement pump.

FIG. 10 is a schematic view similar to FIG. 9 where the fluid underpressure is supplied from a separate source to the timing portion of themulti-valve control device. The timing gears are employed as a motor toopen and close the respective valves. The rate of percussion imparted bythe piston may be controlled with a flow control valve controlling therate of flow to the timing gears.

FIG. 11 is a schematic view similar to FIG. 9 in which separate drivemeans are provided for the timing device to open and close therespective valves. With this arrangement, the percussion rate can bevaried over a wide range.

FIG. 12 is a perspective view of pairs of the disc-like valve elementswith shafting connecting axially aligned pairs of disclike valveelements.

FIG. 13 is a view partially in section of a percussion drill head withthe cylinder housing and a reciprocating piston having pairs of openingson opposite sides of the piston.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings andparticularly to FIG. 3, there is illustrated a drill head generallydesignated by the numeral 10 that includes a cup-shaped housing 12 withan annular open top portion 14 and a base portion 16. The side wall ofthe housing 12 has an opening 18 in which bearings 20 are positioned tosupport a rotatable shaft 22. A bevel gear 24 is connected to the shaft22 within the housing 12. Suitable means, not illustrated, are arrangedto rotate the shaft 22 and thus impart rotation to a drill rod 26, aslater explained. A top plate 28 encloses the housing opening 14 and issecured to the housing 12 by means of bolts 30. The plate 28 has anupstanding annular collar portion 32 with an annular passageway 34connected to an outlet opening 36 for removing the dust and cuttingsconveyed through the internal passageway 38 of the drill rod 26.

Positioned within the ,housing 12 is a drill rod support member 40 thathas a base portion 42 and a cylindrical side wall 44. A bevel gear 46 issecured to the outer portion of the cylindrical wall 44 and meshes withthe bevel gear 24 to thereby rotate the drill rod support within thehousing 12. Suitable thrust bearings 48, and 52 are arranged between thehousing 12 and the drill rod support member 40 to permit rotation of thedrill rod support member relative thereto. The upper portion of thedrill rod support member has a socket 54 for receiving a drill rodtherein. The drill rod, however, is free to move axially in the socket54 so that percussive forces imparted thereto are transmitted throughthe drill rod to a drill bit connected to the opposite end thereof.

The drill rod support member 40 has an opening 56 in the base portion 42in which there is positioned a bearing 58. The support member 40 has anaxial passageway 60 therethrough aligned with the opening 56 in whichthere is positioned a hammer shaft 62. The end portion 64 of the hammershaft 62 extends through the opening 56 in the support member 40 intothe inner portion of housing 12. The hammer shaft 62 has an enlargedother end portion 66 which is positioned in the upper portion of thedrill rod support member and is in abuttingrelation with the base of thedrill rod 26 and is operable upon axial reciprocatory movement to impartpercussive strokes to the drill rod 26.

A cylinder generally designated by the numeral 68 has a body portion 70and end flange members 72 and 74. The end flanges 72 and 74 are securedto the body portion 70 and to the housing base portion 16 by means ofbolts 76 and are axially aligned with the hammer shaft 62. The bodyportion 70 has an inner cylindrical chamber 78 with an upper annularshoulder portion 80 and a lower annular shoulder portion 82 thatprovides upper and lower cylindrical chamber portions 84 and 86 ofreduced diameter. Positioned within the cylindrical chamber portions ofreduced diameter are annular bearings 88 and 90. A piston generallydesignated 92 has an annular recessed portion 94 in which a piston ring96 is positioned. The piston 92 has substantially the same diameter asthe cylindrical chamber 78 of cylinder 68 so that fluid under pressureacting on the upper annular surface 98 of piston 92 moves the piston 92downwardly in the body portion 70. Similarly, fluid pressure acting onthe lower annular surface 100 moves the piston upwardly within thecylinder body portion 78.

The piston 92 has a pair of oppositely extending cylindrical shafts withintermediate portions 102 and 104. The diameter of the intermediateportions 102 and 104 is substantially the same as the diameter of thecylindrical chamber portions 84 and 86. There is approximately .002 inchclearance between the surfaces of intermediate portions 102 and 104 andthe inner cylindrical wall of chamber portions 84 and 86. With thisarrangement, as the cylinder 92 is reciprocated so that the intermediateshaft portions 102 or 104 are moved into the cylindrical chamberportions 84 or 86, the fluid entrapped within the chamber portionsserves as a liquid cushion for the piston. Because of the slightclearance between the intermediate shaft portions 102 or 104 and theside walls of the chamber portions 84 and 86, the fluid is slowlydisplaced to thereby provide a fluid cushion for the piston 92. Thereare provided passageways 106 and 108 in the flanges 72 and 74 to receiveand return to the tank, the fluid that has leaked past the bearings 88and 90.

The oppositely extending shafts of piston 92 have end shaft portions 110and 112 extending therefrom. The end shaft portions are suitablypositioned in the annular bearings 88 and 90 to maintain the piston 92axially aligned within the cylinder 68. The shaft end portion 110extends through an opening 114 in the drill head housing bottom portion16 and has an end surface 116 in abutting relation with the end portion64 of hammer shaft 62. With this arrangement, upward movement impartedto the piston 92 is transmitted through the shaft end portion 110 to theend surface 116 which, in turn, strikes the end portion 64 of hammershaft 62 and moves the hammer shaft upwardly within the drill rodsupport member 40. Since the upper portion 66 of hammer shaft 62 is inabutting relation with the base of drill rod 26, this upwardlypercussive force or motion is transmitted to the drill rod 26. Since thedrill rod is continually urged against the base of the hole beingdrilled by the drilling machine, the drill rod 26 and hammer shaft 62are moved downwardly within the drill rod support 40 when the piston 92is moved downwardly within the cylinder 68. Thus, each upwardly movementof the piston 92 imparts an upwardly percussive blow to the drill hammer62 which is, in turn, transmitted to the drill rod 26. Positive fluidpressure is employed to move the piston 92 downwardly away from thedrill hammer end portion 64.

The cylinder body portion 70 has an upper inlet port 118 opening intothe cylindrical passageway 78 within the body portion 70 and an upperoutlet port 120. lt should be noted in the particular embodimentillustrated, the inlet port 118 and outlet port 120 both communicatewith the cylindrical chamber 78. An inlet conduit 122 is connected toinlet port 118 and vent conduit 124 is connected to outlet port 120.Similarly, the cylinder 68 has a lower inlet port 126 below the piston92 and an outlet port 128. Conduits 130 and 132 are connected to therespective inlet and outlet ports 126 and 128. With this arrangement,fluid supplied through inlet conduit 122 will fill the annular chamberbetween the cylindrical intermediate shaft portion 102 and thecylindrical walls of chamber 78 and displace or move the cylinder 92downwardly. Since the lower portion of the cylinder is vented throughoutlet conduit 132, fluid remains in the annular chamber between theshaft 112 and the cylindrical wall of chamber portion 86. Theintermediate shaft member 104 has a shoulder or secondary piston face135 that contacts the fluid within the annular chamber designated by thenumeral 134 and, with the clearance between the surface of intermediateshaft portion 104 and wall 86, the fluid slowly flows therebetween andprevents metal to metal contact on the upward and downward strokes ofthe piston.

Referring to FIGS. 1 and 2, there is illustrated a multi-port controldevice generally designated by the numeral 136 that has an upper ventvalve 138, an upper pressure valve 140, a lower pressure valve 142, alower vent valve 144 and a timing device pump combination 146. The uppervent valve 138 has a port 148 to which conduitl24 is connected. Theother end of conduit 124 is connected to vent port 120 of cylinder 68(FIG. 3). A pressure accumulator generally designated by the numeral 150is connected in series with the conduit 124 and port 148. The upperpressure valve 140 has a port 152. Conduit 122 is connected to port 152and to port 118 of the cylinder 68 (FIG. 3).

The lower pressure valve 142 has a port 154 connected to conduit 130.The other end of conduit 130 is connected to the lower pressure port 126in cylinder 68. The lower vent valve 144 has a port 156 that isconnected to conduit 132. The other end of conduit 132 is connected tothe lower vent port 128 in cylinder 68. A pressure accumulator 158 isconnected in series with the conduit 132 and port 156 of vent valve 144.

The multi-valve control device 136 includes an end plate 160 with aplurality of longitudinal bolt passageways 162 therethrough adjacent thecircumferential edge portion and a pair of recessed cup-shaped portions164 and 166. Annular bearings 168 and 170 are positioned in the recessedportions 164 and 166. The upper vent valve 138 includes a pair ofdisclike valve members 172 and 174 with peripheral grooved portions 176and 178 extending around about 180 to of the periphery. The member 172has oppositely extending shaft end portions 180 and 182. The shaft endportion 180 is positioned in the bearing 168 in recess 164. Similarly,the member 174 has oppositely extending shaft end portions 184 and 186.The shaft end portion 184 is rotatably positioned in bearing 170 inrecessed portion 176. An annular valve housing 188 having port 148therein extends around the pair of disclike members 172 and 174 and hasa central chamber therein. The housing is similar to that illustrated inFIGS. 5 and 6. The valve housing 188 has longitudinally extending boltapertures 190 aligned with the bolt apertures 162. The valve housing hasone planar end wall 192 in abutting relation with a mating end wall ofthe end plate 160 to form a seal therebetween. A support housing 194 hasa plurality of bolt passageways 196 aligned with bolt passageways 190and 162 and has a pair of longitudinal passageways 198 and 200 withenlarged end portions 202 and 204 adjacent the opposite end wall 207 ofvalve housing 188. Bearings 206 and 208 are positioned in enlargedportions 202 and 204 and shaft end portions 182 and 186 of disc-likevalve members 172 and 174 are rotatably supported in the bearings 206and 208. The passageways 198 and 200 have enlarged portions 210 and 212in which bearings 214 and 216 are positioned.

The upper pressure valve 140 has a pair of disc-like valve members 218and 220 which are similar to the disc-like valve members 172 and 174previously described. The disc-like valve member 218 has a shaft portion222 positioned in the recessed portion 210 of support member 194 anddisc-like valve member 220 has a shaft end portion 224 positioned in theenlarged portion 212. The disc-like valve members 218 and 220 haverecessed peripheral portions 226 and 228 similar to the recessedportions 176 and 178 that extend around 190 of the periphery of both ofthe valve members 218 and 220. The shaft end portions 182 and 222 haveaxial passageways 230 and 232 therein with suitable keyways 234 and 236.A shaft 238 is positioned in the passageway 198 of support member 194and extends into the recessed portions 230 and 232 and is suitably keyedto the end shaft 182 and 230 so that valve members 172 and 218 rotate intimed relation to each other.

The disc-like valve member 220 is similarly connected to disc-like valvemember 174 by means of shaft 240 keyed to the shaft end portions 186 and224. As illustrated in FIG. 2, the upper vent valve 138 is open in thatthe peripheral recessed portions 176 and 178 are facing each other andin overlying relation to form a passageway therebetween. The upperpressure valve 140 is closed in that the recessed portions 226 and 228are spaced from each other. The upper pressure valve 140 has an externalhousing 242 which is similar in construction to the external housing 188of the vent valve 138. The housings 188 and 242 and the disc-like valvemembers housed therein are interchangeable.

Abutting the wall of valve housing 242 is a support member 244 which issimilar to the support member 194 and is interchangeable therewith. Thesupport member 244 has passageways 246 and 248 extending therethrough inwhich shafts 250 and 252 are positioned and extend into recessedportions within the shaft end portions of disc-like valve members 218and 220.

The lower pressure valve 142 is positioned adjacent the support member244 and has a housing 254 which is similar to the housings 242 and 188.Within the housing 254 there are positioned a pair of disc-like valvemembers 256 and 258 which have peripheral recessed portions 260 and 262.The disc-like valve members 256 and 258 are of the same construction asthe previously described disc-like valve members and have shaft endportions 264 and 266, 268 and 270. The shaft end portions 264 and 268extend into enlarged passageways in the support member 244 and haverecessed portions 272 and 274 in which the shafts 250 and 252 arepositioned and nonrotatably keyed thereto so that the disc-like valvemembers 256 and 258 rotate in timed relation with the other previouslydescribed disc-like valve members. A support member 276 similar tosupport members 244 and 194 is positioned in abutting relation with theupper pressure valve housing 254 and has passageways 278 and 280therethrough in which shafts 282 and 284 are positioned. The shafts 282and 284 extend into recessed portions of disc-like valve member shaftend portions 266 and 270 and are keyed thereto.

The lower vent valve 144 has a housing 286 in which a pair of disc-likevalve members 288 and 290 are positioned with recessed peripheralportions 292 and 294. The disc-like valve members have shaft endportions 296, 298, 300 and 302. All of the shaft end portions haverecessed portions therein and shafts 282 and 284 extend into therecessed portion of shaft end portions 296 and 300 and are keyed thereinto rotatably connect the disc-like valve members 288 and 290 to thedisclike valve members 256 and 258 and the other previously describedvalve members. It should be noted that the disc-like valve members 256and 258 of the lower vent valve have their recessed portions 260 and 262abutting each other to form a passageway therebetween so that the lowervent valve as illustrated in FIG. 2 is open, whereas the lower pressurevalve 144 is closed because the recessed portions 292 and 294 are spacedfrom each other.

FIG. 12 illustrates in detail the manner in which the pairs of disc-likevalve members 256 and 258 are connected to the adjacent pair ofdisc-like valve members 288 and 290 by means of the shafts 282 and 284.It should be understood that the disc-like valve members may have eithera longitudinal bore therethrough or recessed portions to receive endportions of the shafts therein. The plurality of shafts connecting theadjacent axially aligned disc-like valve members may be referred to asshafting connecting the respective disc-like valve members.

Another support member 304 is positioned in abutting relation with thevalve housing 286 and is similar in construction to the previouslydescribed support members. The support member 304 has passageways 306and 308 in which shafts 310 and 312 are positioned. The shaft 310extends into a recessed portion of shaft end portion 298 and is keyedtherein. Similarly, shaft 312 extends into a recess in shaft end portion302 and is also keyed therein.

The combination timing device and positive displacement pump 146 has ahousing 314 positioned in abutting relation with the support member 304.The housing has longitudinal bolt passageways 316 and a pair of meshinggears 318 and 320 are positioned in the housing 314. The gear 318 hasshaft end portions 322 and 324. Similarly, the gear 320 has shaft endportions 326 and 328. The shaft end portions 322 and 326 are positionedin the enlarged portions of passageways 306 and 308 and shaft 310 and312 extend into recessed portions of the respective gears 318 and 320and are keyed thereto so that gears 318 and 320 are connected to thepreviously described disc-like valve members.

An end plate 330 has bolt receiving apertures 332 and a cup-shapedrecessed portion 334 for receiving the shaft end portion 324 of gear318. The end plate 330 has a passageway 336 with an enlarged portion338. The shaft end portion 328 of gear 320 is supported in the enlargedportion 338 of passageway 336. A drive shaft 340 has an end portionextending into an axial passageway 342 of gear 320 and is keyed theretoso that rotation of shaft 340 rotates both gears 318 and 320 and by thepreviously described connections all of the disc-like valve memberswithin the multi-port control device 136. The end plate 330 has a motormounting bracket 344 thereon arranged to support a drive motor or thelike con nected to the shaft 340. It should be understood, however, theuse of the shaft 340 as a driving means is optional, as later described.

The previously described valve members are positioned in stackedrelation as illustrated in FIGS. 1 and 2 and are secured in thisposition by the elongated bolts 346 extending through the bolt aperturespreviously described. Referring to FIG. 1, the support member 194 has anoutlet port 348 therein and an internal passageway 350 that is connectedto an internal passageway 352 in the upper vent valve housing 188. Thesupport member 244 has a port 354 that opens into passageway 356. Thepassageway 356 is connected to passageways 358 and 360 in valve housings242 and 254 of the upper and lower pressure valves and 142 respectively.The support member 276 has a port 362 opening into passageway 364 whichis connected to a passageway 366 in the housing 280 of lower vent valve144. The support member 304 has a pair of ports 368 and 370 that openinto respective passageways 372 and 374. The housing 314 has passageways376 and 378 that are connected to the passageways 37-2 and 374respectively.

As previously stated, the valves 138, 140, 142 and 144 are of similarconstruction and some of the elements thereof are 101011 Allinterchangeable. Similarly, the support members 194 and 276 are ofsimilar construction and are interchangeable. The support member 244differs from support members 194 and 276 in that the passageway 356opens into both valves 140 and 142. The support member 304 also has apair of ports 368 and 370 and passageways 372 and 374.

FIG. is a sectional view in elevation of the lower pressure valve 142and illustrates the housing 254 with the peripheral bolt passageways forbolts 346 and the disc-like valve members 256 and 258 with theperipheral recessed portions 260 and 262. In FIG. 5, the recessedportions 260 and 262 are illustrated as extending around 180 of thedisc-like valve member periphery. In FIG. 6, however, the recessedportions 292 and 294 are, for illustrative purposes, illustrated asextending around about 190 of the disc-like valve member periphery. Itis preferred to have the same peripheral recessed portion for all of thedisc-like valve members so that the plurality of valves will open andclose in timed relation. Where the recessed portions extend around 180of the periphery, the volume of liquid displaced by the timing gears 318and 320 in one-half a revolution should be about percent greater thanthe volume of liquid required to displace the piston in the cylinder fora complete stroke of the piston. The excess fluid enters an accumulatorin the conduit connecting outlet port 370 from the timing device pumpcombination 146 and the inlet port 354 for pressure valves 140 and 142.The accumulator is not shown but may be similar to the accumulators 150or 158. With this arrangement, an accumulator must be provided in theconduit between ports 370 and 354 because all of the valves in thecontrol device are closed and the excess volume of fluid supplied by thetiming device pump combination 146 must be displaced in the accumulator.

Where the recessed portions extend around 190, the accumulator in theconduit connecting ports 370 and 354 is not necessary because there isan overlap where both pressure valves 140 and 142 are open for about 10of the revolution. The metering gears should, however, be made larger tocompensate for the loss of fluid while all valves are open during the 10overlap. The dimension of the timing gears and the piston and cylindermay be varied to control the amount of fluidentering the accumulator 150and the resilience of the spring 394 may be varied to control the forceexerted by the piston in the cylinder.

In FIG. 5, the ports 154 and passageway 360 communicate through themating recessed portions 260 and 262 of the disclike valve members 256and 258 when positioned as illustrated in FIG. 5 so that liquid suppliedto passageway 360 flows through the openings formed by the matingrecessed portions 260 and 262 to the port 154. The disc-like valvemember 256 is illustrated in FIG. 8 with the recessed portion 260 andthe shaft end portions 264 and 266. The shaft 250 is illustrated asextending into a recessed portion of shaft end portion 264 and is keyedtherein. Similarly, the shaft 282 extends into a recessed portion ofshaft end portion 266 and is keyed thereto.

FIG. 6 is a sectional view in elevation of the lower vent valve 144 andillustrates the disc-like valve members 288 and 290 within the housing286. The recessed portions 292 and 294 are spaced from each other andthe passageway 366 does not communicate with the port 156 because theperipheral portions of the disc-like valve members 288 and 290 areabutting each other and close the opening between the passageway 366 andport 156.

FIG. 7 is a sectional view in elevation of the metering pump device 146.The housing 314 has passageways 376 and 378 that open into a chamber 380in which the gears 318 and 320 are positioned in meshing relation toeach other. The gears 318 and 320 are arranged upon rotation to displacefluid between the meshing gear teeth and thereby positively displacefluid for flow from one passageway to the other through chamber 380. Thevalve housings, as for example, valve housings 254 and 286, also includea chamber 382 that communicates with the opposed passageways. Thedisc-like valve members, as for example, valve members 256 and 258 invalve 142, are positioned in the chamber 382 and upon rotation permitthe flow of fluid through the chamber from one port to the other or whenin the position as illustrated in FIG. 6, close the chamber 382 andprevent the flow of fluid therethrough from one passageway to the other.

It should be noted as illustrated in FIG. 2, that the disc-like valvemembers are so connected to the adjacent disc-like valve members thatwhen the upper vent valve is opened, as illustrated in FIG. 2, the upperpressure valve 140 is closed and the lower pressure valve 142 is openand the lower vent valve 144 is closed. With this arrangement, asillustrated in FIG. 2, fluid under pressure is being supplied throughlower pressure valve 142, conduit 130, to the face of piston 92 (FIG. 3)to move the piston 92 upwardly. When the lower vent valve 144 is closed,the upper vent valve 138 is opened to permit the fluid within thecylinder above the piston 92 to be displaced through conduit 124. Theupper pressure valve 242 is closed so that fluid under pressure is notbeing supplied to the upper portion of the cylinder 68. Where theperipheral recessed portions extend around more than 180 of thedisc-like valve member periphery, there is a slight overlap where, for ashort period of time, both the vent and pressure valves are open.

A suitable pressure accumulator such as accumulator 150 or 158 ispositioned in series with the conduits 124 and 132 and ports 148 and 156of the vent valves 138 and 144 to displace fluid supplied to thecylinder in excess of the volume of the annular space between the pistonand the cylinder. One of the pressure accumulators is illustrated indetail in FIG. 4 and includes a cylindrical housing 384 with a baseportion 386 that has a longitudinal passageway 388 that is connected inseries with the conduit 124 and the port 148. The housing 384 has anopening 390 into the passageway 388. Within the cylindrical housing 384there is positioned a piston 392 and a coil spring 394 that urges thepiston toward the base 386. An adjusting device 396 is provided toincrease or decrease the tension on spring 294. An exhaust port 398 isprovided above the piston 392 to vent the slight amount of fluid thatleaks past the piston 392 within the housing 384. The piston 392 isdisplaced upwardly by the excess fluid supplied to the cylinder 68 (FIG.3). When the vent valve is opened the piston 392 displaces the fluidwithin the housing 384 into the conduit 124.

In FIG. 13 there is illustrated a percussion drill that includes apiston cylinder assembly similar to that illustrated in FIG. 3. Similarnumerals in FIG. 13 will designate similar parts of the piston cylinderassembly.

The percussion drill in FIG. 13 is generally designated by the numeral550 and includes a chuck housing 552, a piston cylinder assembly 554 anda drill indexing housing generally designated by the numeral 556. Thechuck housing 552 and drill indexing housing 556 are secured to thecylinder 68 by the bolts 76 and are axially aligned. The chuck housing552 includes a chuck 558 with a central bore 560 in which the base 562of drill rod 564 is positioned. The drill rod 564 is movable verticallyin the chuck 558 and is rotatable by means of the indexing housing 556,later described. The piston cylinder assembly 554 has the piston endportion in abutting relation with the end portion of drill rod 564. Asleeve member 566 nonrotatably secures the drill rod 564 to the pistonend portion 110 so that rotation of piston 92 by means of indexingmechanism 56 is transmitted to the drill rod 564.

The cylinder 68 has a pressure inlet port 118 and a pressure outlet port120 above the piston 92 and pressure inlet port 126 and pressure outletport 128 below the piston 92 as previously described in reference toFIG. 3. With this arrangement, fluid supplied through conduit 122 to thecylinder 68 moves the piston 92 downwardly and moves the end of thedrill rod 564 away from the base of the hole being drilled. Fluidsupplied through conduit 130 moves the piston 92 upwardly to transmitthrough the shaft 110 upward percussive movement to the drill rod 564.Thus, reciprocation of piston 92 within cylinder 68 provides thepercussive blows to the base of the drill rod 564 to thereby dislodgematerial in the hole being drilled.

The end shaft section 112 has splined portions 568 which nonrotatablyconnect the piston 92 to an indexing mechanism generally designated bythe numeral 570 that is housed within the drill indexing housing 556.The drill indexing mechanism 570 may be conventional and similar to theindexing mechanisms illustrated in US. Pat. No. 3,059,618 and US. Pat.3,044,448. The indexing mechanism 570 is so arranged that on the returndownward stroke of the piston 92, the piston rotates through a fractionof a revolution to thereby rotate and index the drill bit for the nextpercussive stroke. The rotation of the piston 92 is transmitted throughthe sleeve 566 to the drill rod 564. Thus, with the above describedarrangement, it is now possible to provide percussive forces to areciprocating percussion drill with a fluid supplied to the pistoncylinder assembly 554 from the multi-port control device 136 illustratedin FIGS. 1 and 2.

The high speed rotary percussion drill illustrated in FIG. 3 operates asfollows. The drill rod support member 40 and the drill rod 26nonrotatably connected thereto is rotated at high rotary speed by meansof drive shaft 22 transmitting rotation through bevel gears 24 and 46.The hammer shaft 62 and the piston 92 rotate at substantially the samespeed as the drill rod support member 40. The percussive forces areimparted to the drill rod 26 by supplying fluid under pressurealternately through conduits 122 and 130 from the multi-port controldevice 136.

It will be appreciated that the previously described multiport controldevice 136 can be utilized to provide reciprocatory motion for thepiston 92 within cylinder 68. FIGS. 9, and 11 schematically illustratevarious arrangements for supplying the fluid under pressure to theopposite faces of the piston 92 within the cylinder 68. Although notillustrated in FIGS. 9, 10 and 11, it should be understood thataccumulators 150 and 158 are positioned in the conduits 124 and 132 asillustrated in FIG. 1. In FIG. 9, a motor 500 is connected to shaft 340and is arranged to rotate the gears 318 and 320 within the combined pumpand timing device 146. In the embodiment illustrated in FIG. 9, thetiming device pump combination 146 serves both as a timing device and asa positive displacement pump. The port 370 is connected to a source offluid by a conduit 502. The fluid displaced by the gears 318 and 320flows through conduit 504 into passageways 360 and 358 of the upper andlower pressure valves 142 and 140 respectively. Where the recessedportions of the valves extend around 180 of the periphery, a pressureaccumulator is positioned in conduit 504. The upper pressure valve 140is connected by means of conduit 122 to the cylinder 68 and the lowerpressure valve 142 is connected by conduit 130 to the cylinder 68 aspreviously described. The upper vent valve 138 is in turn connected byconduit 124 to the cylinder 68 and the lower vent valve 144 is connectedby conduit 132 to the lower portion of cylinder 68. The vent valves 138and 144 are connected by means of conduits 506 and 508 to a reservoir ortank 510. With this arrangement, the metering gears may be so sized thatthey will displace the same amount of fluid in one-half of a revolutionas is displaced in one end of the cylinder. Where the metering gearshave a greater displacement, a pressure accumulator must be positionedin conduit 504 to take up and displace the excess fluid supplied by themetering gears in one-half a revolution.

In FIG. 10, a separate pump 512 is provided, driven by the motor 500.The fluid under pressure from pump 512 is supplied through conduit 514to the timing device 146. The fluid under pressure rotates the gears andopens and closes the valves as previously discussed and supplies thefluid under pressure through conduit 514 to the pressure valves 140 and142. With this arrangement, the metering gears should have the samedisplacement in one-half revolution as the displacement in one end ofthe cylinder. Where the metering gears displace greater volumes offluid, an accumulator should be positioned in conduit 504.

FIG. 11 illustrates an arrangement where fluid under pres sure isdelivered from the pump 512 directly to the pressure valves and 142. Aseparate variable speed motor 516 is connected to a speed reducer 518and the shaft 340 of the timing gears 318 and 320. A separate source oflubricant is supplied to the timing gears in this embodiment. With thisarrangement, the motor 516 controls the opening and closing of thepressure and vent valves and also controls the number of percussivestrokes per unit of time so that one can vary the speed of motor 516 andthereby vary the percussive strokes over a relatively wide range.

According to the provisions of the patent statutes, I have explained theprinciple, preferred construction and mode of operation of my inventionand have illustrated and described what I now consider to represent itsbest embodiment. However, it should be understood that, within the scopeof the appended claims, the invention may be practiced otherwise than asspecifically illustrated and described.

lclaim:

1. A control valve assembly comprising,

a first pressure valve, a first vent valve, a second pressure valve anda second vent valve,

certain of said valves include a pair of disc-like valve memberspositioned in side-by-side relation and having aligned peripheralrecessed portions extending around about of said disc-like periphery,

. said pair of valve members positioned in abutting relation with saidrecessed portions in face-to-faee relation and forming an openingtherebetween for the flow of fluid therethrough, and

mechanical means connecting said valves so that said first pressurevalve is open and said first vent valve is closed when said secondpressure valve is closed and said second vent valve is open.

2. A control valve assembly as set forth in claim 1 which includes,

timing means to control the opening and closing of said valves toprovide fluid under pressure to a servomechanism at preselected timeintervals.

3. A control valve assembly as set forth in claim 1 which includes,

metering means to supply a predetermined volume of fluid to aservomechanism through said pressure valves.

4. A control valve assembly as set forth in claim 1 in which,

said disc-like valve members have a peripheral surface comprising aplanar surface extending around about 180 of said disc-like peripheryand a recessed portion extending around about 180 of said disc-likeperiphery,

said pair of valve members positioned in abutting relation with saidrecessed portions in face-to-face abutting relation and closing saidvalve for the flow of fluid therethrough.

5. A control valve assembly as set forth in claim 4 in which,

said mechanical means includes shaft means non-rotatably connected tosaid disc-like valve members, and

timing means to rotate said disc-like valve members in oppositedirections relative to each other to position said recessed portions inface-to-face relation with each revolution of said disc-like members tothereby open said valves during about one half a revolution of saiddisc-like valve members and close said valves during about one halfrevolution of said disc-like valve members.

6. A control valve assembly as set forth in claim 5 in which,

said timing means includes gear means connected to said shaft means andin meshing relation to rotate said disclike valve members in timedrelation to each other.

7. A control valve assembly as set forth in claim 6 in which,

said shaft means includes first shafting connecting one of saiddisc-like valve members of said first pressure valve, first vent valve,second pressure valve and said second vent valve,

second shafting connecting said other disc-like valve member of saidfirst pressure valve, first vent valve, second pressure valve, and saidsecond vent valve.

8. A control valve assembly as set forth in claim 7 which includes,

1 1 K 12 a first spur gear connected to an end portion of said firstcludes,

Shafilng, a housing with said meshing spur gears rotatably supported asecond spur gear connected to an end portion of said therein,

second shafting,

said first and second spur gears in meshing relation with 5 each otherand operable upon rotation to rotate said disclike valve members intimed relation to each other. pump 9. A control valve assembly as setforth in claim 8 which insaid housing have an inlet port and an outletport and forming with said meshing spur gears a positive displacementIll run-11 [\IAA

1. A control valve assembly comprising, a first pressure valve, a firstvent valve, a second pressure valve and a second vent valve, certain ofsaid valves include a pair of disc-like valve members positioned inside-by-side relation and having aligned peripheral recessed portionsextending around about 180* of said disc-like periphery, said pair ofvalve members positioned in abutting relation with said recessedportions in face-to-face relation and forming an opening therebetweenfor the flow of fluid therethrough, and mechanical means connecting saidvalves so that said first pressure valve is open and said first ventvalve is closed when said second pressure valve is closed and saidsecond vent valve is open.
 2. A control valve assembly as set forth inclaim 1 which includes, timing means to control the opening and closingof said valves to provide fluid under pressure to a servomechanism atpreselected time intervals.
 3. A control valve assembly as set forth inclaim 1 which includes, metering means to supply a predetermined volumeof fluid to a servomechanism through said pressure valves.
 4. A controlvalve assembly as set forth in claim 1 in which, said disc-like valvemembers have a peripheral surface comprising a planar surface extendingaround about 180* of said disc-like periphery and a recessed portionextending around about 180* of said disc-like periphery, said pair ofvalve members positioned in abutting relation with said recessedportions in face-to-face abutting relation and closing said valve forthe flow of fluid therethrough.
 5. A control valve assembly as set forthin claim 4 in which, said mechanical means includes shaft meansnon-rotatably connected to said disc-like valve members, and timingmeans to rotate said disc-like valve members in opposite directionsrelative to each other to position said recessed portions inface-to-face relation with each revolution of said disc-like members tothereby open said valves during about one half a revolution of saiddisc-like valve members and close said valves during about one halfrevolution of said disc-like valve members.
 6. A control valve assemblyas set forth in claim 5 in which, said timing means includes gear meansconnected to said shaft means and in meshing relation to rotate saiddisc-like valve members in timed relation to each other.
 7. A controlvalve assembly as set forth in claim 6 in which, said shaft meansincludes first shafting connecting one of said disc-like valve membersof said first pressure valve, first vent valve, second pressure valveand said second vent valve, second shafting connecting said otherdisc-like valve member of said first pressure valve, first vent valve,second pressure valve, and said second vent valve.
 8. A control valveassembly as set forth in claim 7 which includes, a first spur gearconnected to an end portion of said first shafting, a second spur gearconnected to an end portion of said second shafting, said first andsecond spur gears in meshing relation with each other and operable uponrotation to rotate said disc-like valve members in timed relation toeach other.
 9. A control valve assembly as set forth in claim 8 whichincludes, a housing with said meshing spur gears rotatably supportedtherein, said housing have an inlet port and an outlet port and formingwith said meshing spur gears a positive displacement pump.